That 48 quart probably is gonna be too thin a grain bed with a partial mash...your grainbed won't filter well. that's my thoughts at least.
I'd go with the 10gallon round cooler.
I assume you just can't handle a 7 gallon boil right now? You can PM as much as you can manage to boil. I did a big PM using two smaller stock pots, so I only had to add 1 gallon of top off water.
Its not the best setup, but it worked well for me until I could drop the cash for AG.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10